This proposal describes a comprehensive research project designed to prospectively pilot test the efficacy of prolonged exposure (PE) therapy at reducing symptoms of HIV-related posttraumatic stress disorder (PTSD) and increasing adherence to antiretroviral medication regimens in people living with HIV (PLWH). Recent studies examining the efficacy of cognitive behavioral interventions at increasing adherence to medications in PLWH have produced, at best, small effect sizes. Failure to address mental health issues in PLWH has been suggested as one explanation for the relatively small impact of these interventions. Previous research has found that symptoms of PTSD (particularly avoidance symptoms stemming from diagnosis/living with HIV) are positively related to non-adherence. PE has been found to be an effective treatment for PTSD; however, its efficacy at reducing PTSD symptoms in patients meeting criteria due to diagnosis with a life-threatening disease is unknown. Further, the extent to which decreasing symptoms of PTSD results in consequent reductions in non-adherence has not been examined. The proposed research will examine the efficacy of PE therapy at reducing HIV-related PTSD and non-adherence in 70 PLWH (20% female, 50% African-American, 50% Caucasian) with PTSD. Participants will be randomly assigned to either the 6-week, 12-session intervention or a weekly monitoring/wait list control group. Follow-up time points at post treatment and three and six months will consist of interviews and questionnaires designed to measure symptoms of HIV-related PTSD and co-morbid disorders. Further, medication adherence (via self-report and electronic monitoring) will also be measured. The proposed research will directly test the efficacy of PE at reducing symptoms of HIV-related PTSD and co-morbid disorders, and non-adherence, and will provide pilot data and effect sizes for a large-scale randomized, multi-site trial.